Lifting jack



0a. 6', 1931. H.; NEWTON 1,825,702

LIFTING JACK Filed June 18,'1927 L @T B Ulu :15:

TTUR/VEYS Patented Oct. 6, 1931 UNITED STATES HERBERT EDVIN NEWTON, OF TNBBIDGE, ENGLAND LIFTING J ACK Application filed June 18, 1927, Serial No. 199,683, and in Great Britain March 3, 1927.

My invention hasfor its object a lifting A jack of such construction that it may be completely operated by a single movement to raise a body, and when such movement is completed it will be automatically locked, but can be released and the raised body lowered by a simple reverse movement of the lever handle.

Such jack I construct of the usual base and a3 body in which latter slides telescopically the lifting ram.

This ram is adapted to be engaged and operated by one end of a lever, and this lever is fulcrumed in the free end of a link hinged 5 at its opposite end to the jack base, and said link is of such length and is so situated that when the tree end of the lever isoperated to its full extent to completely raise the ram, said link assumes a position in which it locks the lever against spontaneous movement in the opposite direction.

The relative lengths of the lever arms are proportioned to ensure the required lift of the ram, while to enable the ram to be fully opi5 erated by a single movement of the lever handle the powerI arm of the leveris connected to the lower part of the ram, and the two arms of the lever are set at such an angle to one another that the lever handle is inclined to the jack body when raised, and occupies an approximately horizontal position when depressed.

The link is preferably made less than halt` the length of the power arm of the lever and is so positioned that it generally inclines inwards and does not pass the vertical while the ram is being raised, the object being to reduce the lateral pressure and consequent friction on the ram during its upward travel. A jack so constructed is illustrated by the accompanying drawings, and I will further describe my invention and the manner in which it may be carried into practical eifect by the aid thereof.

Ot these drawings Figure l is a side elevation, parts being broken away, Figure 2 a front elevation, and Figure 3 a plan of such i ack.

As so shown the jack comprises a body A mounted on a base B and forming the frame,

a ram C, mounted to slide telescopically in said body, and an operating lever D, having the two arms thereof set at an angle to one another, and which lever is fulcrumed on the free end of a link E the opposite end of which is hinged to the base B.

The power arm of the lever D passes through a slot in the body A and is connected to the lower slotted end of the ram C by a pin c passing through the two so that, when the lever is operated to raise the ram, the end or" the power arin of the lever will travel in a straight path, instead of the usual curved one, and the lever fulcrum will follow such movement and so cause the link E to rock in- G5 wards. The lowest portion of the lower edge of the power arm will rest upon the base of the jack both when said arm is fully raised and lowered. At all times during the operation of the jack, the link will be in an in- YU wardly inclined position relative to the ram and will not pass beyond the vertical plane extending through the point of connection of the link with the base B.

rlhe length oi the link E and thepositions in which it is connected to the lever D and the base B are such, that this inward rocking of the link, when the lever is operated, results in the connection between the lever andthe link assuming a position relative to so that between the link and the base, to lock the lever, as shown in dotted lines in Figure 1, against movement lin the opposite direction.

It is also to be noted that the relative distances of the lever ulcrum from the base- S5 line of the jack and from the ram are such i that, with the fulcrum link inclined inwardly toward the ram, a stabilizing inward thrust is given to the power arm of the lever t`o counterbalance the pull on the lever handle when the jack is operated. Itis further to be noted that the angle between lines extending from the points of connection of the power arm of the lever to the ram, and to the fulcrum of said arm, and from the former to the point of connection of the fulcruin link E to the baselof the frame is not more than thirty degrees.

The operating arm of the lever D may be made in two parts fitted with a socket joint as shown, to permit of easy connection and detachment for convenience of transport, while the length of the ram C may be made adjustable as illustrated, to permit of the height of the jack being varied as desired, by fitting it with a headpiece el, the stem of which slides in the upper end of the -ram and is supported by a pin c2 passing through one of a series of holes in said stem.

Although the operating arm has been shown and described as being operable in a downward direction in order to raise the ram C, it is understood that the relative positions of the parts may bechanged, without departing from the spirit or scope of the invention, so that a lift-ing of said arm vmay be utilized -to raise said ram.

Havingnow particularly described and as- `certainewlthe lnature of my `invention and the manner in whichthe same is to be performed I declare that what Iclaim is:-

1. A lever jack comprising a frame, a ram slidable vertically therein, a link hinged to said `frame and having an inwardly inclined position whenfthe ram is lowered, and a lever including operating and power arms for operatingsaid ram, said lever fulcrumed in said linkrand locked thereby when its power arm is fully operated by a single movement of the operating arm to completely raise the ram, said link having an in "ard movement during the operation of said lever to raise the rum, and the movement -of said link during operation of said lever being limited Lto prevent `passage of the link beyond the vertical :plane through its hinge connection withsaid frame.

2. A lever jack comprising a frame, a ram slidable vertically therein, a link 'hinged to `said frame and 4having an inwardly inclined position when the ram is lowered, and a lever including operating and power arms for operating said ram, said lever ulcrumed on said link and locked thereby when its power arm is fully operated by a single movement of the operating arm to completely raise the ram, said link having an inward movement during the operation of said lever to raise the ram, the length of said fnlcrum link being `not more than one-half of the power varm of the lever, and the movement of said link dui ing operation of said lever being limited to `nevent passage of the link beyond the vertical plane through its hange connection with said frame.

3. A lever ack comprising a frame, a ram slidable vertically therein, a link hinged to said frame andhaving an inwardly inclined position when the ram is'lowered, and a lever including operating and power arms for operating said ram, said lever tulcrumed on said link and locked thereby when itspower arm is fully operated by a single movement ofthe operating arm to completely raise the ram, said link `having an inward movement during the operation of said lever to raise the ram, the angle between the lines extending from the points of connection of the power arm of the lever to the ram and to the fulerum of said power arm, and from the former to the point of connection of the fulcrumslink to the base of the frame being not `more than `30", and the movement of said link during operation of said lever being limited to prevent passage of the link beyondv the vertical Aplane through its hinge connection with said frame.

4. A lever jack comprising a. frame, a ram slidable vertically therein, a link hinged to said frame and having an inwardly inclined :position when :the ram is lowered, and a lever includingfoperating and power arms for operating said ram, said lever fulcrumed on said link and locked thereby when its power arm is fully operated `by a single movement of the'opera'ting arm to :completely raise the ram, said llink Vhaving an inward movement during the operation of said lever to raise the ram, :the lowermost portion of the lower edge of the 4power arm of the lever resting on the base of the frame both when said arm' is fully raised and lowered, and the 1novement vof said link during operation of said leverbeing limited to prevent passage of the link beyond the vertical plane through its hingeconnection with said frame.

'In testimony whereof l have signed my name to this specification.

'HERBERT EDVIN NEVTON. 

